The Relative Age Effect: How It Impacts Young Soccer Players

Being the best and brightest is the utmost reward in society. From an early age, we identify cut-off periods for grouping children in both sports and academics. However, a phenomenon has been recognized — those born closest to the cut-off are at an advantage. This phenomenon is known as the Relative Age Effect (RAE).

Annually, The Guardian releases a list of the top 60 best young male players. And annually, the list is composed significantly of players born in the first 6 months of the year. In the 2025 list (2008 birth year), 45 percent were born in Q1 (January-March), with the numbers dropping significantly as you move towards Q4.

 

RAE is evident worldwide at all levels of the game and is a particularly common issue in youth soccer. It often plays a major role in both the success of youth teams and that of individual athletes. Unfortunately, RAE isn’t an easy problem to fix. Yet, there are initiatives at Steel City aimed at minimizing it.

Understanding Relative Age Effect 

Scientists haven’t yet fallen back on the obvious conclusion that being born in January makes you more talented. When the U.S. Soccer cutoff date was September, the ‘best’ players were born in the fall. The advantage simply goes to the oldest players in the group.

To understand RAE, we must distinguish between two types of age:

• Chronological Age: The date on a birth certificate—it’s what we use to group teams.
• Biological Age: How developed a player’s body actually is.

As a person matures biologically, they develop physically, emotionally, and cognitively. In soccer terms, a more mature player can perform better technically, dominate physically, and understand the game more tactically.

Of course, every person grows at a different rate. Research by Johnson et al. (2017) on elite youth soccer players reveals that within a single age group, the biological differences between teammates can range from 5 to 6 years. This means a ‘late blooming’ U12 player could be biologically 9 years old, competing against an ‘early blooming’ teammate who is biologically 14. This creates a massive, albeit invisible, imbalance on the field.

The Knock-on Effects 

“Bigger, faster, stronger” — typical traits of the ‘best athletes’ — do not shine through at the very top level of the game. (The best player in the world currently stands at 5’7”.)

However, in youth soccer, it is all too common to see the most successful teams achieve success through physical dominance. Biologically older players win physical battles, masking their need for technical or tactical improvement. These players often get away with poor technique or slow decision-making because they can make up for it by simply being faster and stronger. But when the playing field levels out in later years, how will they fare?

Conversely, talent identification often fails the smaller player. At a tryout, a biological 15-year-old will likely score more goals and win more duels than a biological 11-year-old. The older player gets selected, gaining access to better coaching and facilities, while the younger player—who may have had more technical potential—is cut.

Bio-banding and U.S. Soccer Initiatives 

To minimize RAE, bio-banding is being looked at on a larger scale. Bio-banding groups players by maturity (85-90% of final growth) rather than birth year. This doesn’t mean every player will be the same height and weight; it means they are at a similar maturational stage and thus will not benefit from unfair biological advantages.

U.S. Soccer began bio-banding initiatives in 2018, and in 2023, the ECNL rules were adapted to allow “trapped” players (U15s not yet in High School) to play down with U14s. While these initiatives are crucial, they challenge clubs to prioritize development over winning. Playing an early-maturing older player “down” just to win a game makes a mockery of the rule. At Steel City, we use bio-banding strictly to help each player reach their highest potential.

What We Do at Steel City to Address RAE

• The Phase Model: With the phase model, all the players are subject to the same education, information, and access to the same coaches. Players work with a different group of coaches over a 2- to 4-year period. With multiple sets of eyes on the players, we are better able to notice when a player needs a greater challenge or more help due to biological maturity. Within the phase, players are pooled for training and given opportunities to train ‘up’ or ‘down’ based on what’s best for their development.
• Steel City Premier League (SCPL): The SCPL was built to do what’s best for players’ development. From inception, we’ve aimed to place individuals in the appropriate match environments. Removing the red tape of a player’s birth year or grade allows common sense to prevail in situations where this tradition of chronological grouping fails the individual.  

With the school year/birth year groupings changing for the 2026/27 season, the already established flexibility in the SCPL means everything will be business as usual. While the general rule of thumb is for players to play with their appropriate new group, our league allows us to make adjustments if the grade change doesn’t work for someone. So ultimately, we’ll just continue on as we have, doing what’s best for each player.

Final Parent Takeaways 

Understanding the science of RAE is a valuable step for parents, yet knowing how to apply this knowledge to support your player’s journey is even more so. Here’s how:

• Trust the Phase Model: Whether your child is moved up, down, or across groups, know that it is done to give them the specific challenge they need right now. Coaches are looking past the physical attributes to find the best environment for your child’s growth.
• Praise Effort, Not Biology: Don’t praise a child for simply being big and fast (genetics), and don’t criticize a child for getting bumped off the ball (biology). Keep your focus on their work rate, bravery, listening, and coachability.
• Focus on the Technical Wins: Don’t judge games just by goals scored or tackles won. Encourage and praise your player for their scanning, first touch, and decision-making. Understand the key performance indicators that we value and that will help guide your players’ technical development and create long-term success.